Hurm. Weird.
It’s a bit hard to log this for a longer period of time using a Navdy (i just had it running a debug firmware and was dumping the whole android logcat into a file), so i guess i’m gonna see what’s going on longer-term on a Kona when my autopi arrives (hasn’t shipped yet).
Not sure if it helps, but I noticed that the battery voltage reported by autopi ( ie measuring the voltage at the obd port) seems different to the “aux battery voltage” reported by OBD PID -
Maybe there is some big voltage drop to the obd port, or perhaps autopi isn’t measuring the voltage very well.
Hmm
I doubt that’s the cause. It’s the same without an Autopi - it appears Hyundais simply don’t have the OBD 12V pin connected directly to the aux battery.
Which makes sense, considering the pin is likely not connected to the aux battery when the car is on or in utility mode (if it has one), like with any acc circuitry in the car.
Okay, i admit, i’ve got no clue whatsoever about what’s going on with voltages in the Kona…
Just retested/remeasured, and got clean 12.6V when off and 14.5V when on.
Weird thing - the voltage lingered around 13.2V for a while after switching the car off.
This time around i’ve used the status/system info display on the navdy itself, still need to check where it’s getting its voltage from in the source, but i’m fairly sure it’s the voltage off the 12V pin, as it most definitely doesn’t know how to read the Hyundai aux battery extended PIDs.
Maybe the voltages reported in the log dumps were uncalibrated.
Sorry for the misinformation, guys.
It just hit me… my aux battery was at about 97-98% SoC two days ago according to Torque. Maybe the aux battery management doesn’t start charging until it drops below a certain threshold (to preserve battery cycles)?
So maybe i wasn’t getting the expected voltage with the car on because of that before, but now that the aux battery SOC dropped from me fooling around with the Navdy and laptop on the parking lot, it started charging with the car on after all.
Hi guys,
What I have noticed with the AutoPi on my Ioniq is that the battery voltage is above 14V while I drive, and then drops down to a little above 12V when I switch off the car.
What you must all remember is that the car’s “usual” functions like air conditioning, headlights, indicators, etc. are all “traditional” components that run off of a 12V system. This is the primary justification for keeping a 12V in an EV… (maybe its only “real” function is to power the remote controlled locking/unlocking systems and alarm)
While driving, the load would be too large for the aux battery on it’s own, so there is a power supply powered off the main (LiPo) battery which powers all the functions (and charges the aux battery), that is why the 12V pin on the OBD connector goes as high as ~14V…
I have not measured the aux battery voltage yet, to confirm if it really goes as high as ~14.7V (if the AutoPi voltage measurement is accurate), but it makes sense for this voltage to climb when the ignition is turned on.
It is also normal to see fluctuations as different functions come on and go off, but in my opinion these drops should be minimal.
I have been thinking that the best solution for AutoPi on EV’s is the following:
Reading the drive motor speed could be achieved with:
obd.query Drive_Motor_Speed mode=21 pid=01 header=7E4 bytes=64 formula='bytes_to_int(message.data[56])*256+bytes_to_int(message.data[57])' unit=rpm baudrate=500000 protocol=6 verify=false force=true
NOTE: the above command does not work, need to figure out how to go about doing that…
Yeah, we’ve already covered this.
The 14V have nothing to do with the main battery - you’ll find the same voltage on ICE cars. 14.2V is the nominal charging voltage for a lead-acid battery, and 14.2-14.3V is what you can measure on the pin as well.
Most of the time.
Because sometimes (like in my case), when the aux battery SOC is high enough, it won’t charge it until it drops, and the voltage will be lower. If the aux battery is in a fairly bad shape, it will likely always be charging when the car is in the on state.
We’ll need to keep the autopi on whilst charging, so that will need to taken account of as well.
I think you can check RPM || ((SOC query) == DATA ) go ON , anything else